Self-regulation is a process that helps students manage their thoughts, behaviours, and emotions to successfully navigate their learning experiences. This process involves students' purposeful actions and efforts directed toward acquiring information or skills. The main objective of this study is to analyze the relationship between self-regulated behaviour and academic achievement among secondary-level students. The investigator used the survey method and selected the sample using random sampling techniques. In this study, 295 ninth-grade students from government, private, and government-aided schools in the Erode district were selected as a sample. The findings of the study indicate a significant difference in the self-regulated behaviour of students from government, aided, and private schools. Additionally, a significant relationship exists between self-regulated behaviour and the academic achievement of secondary-level students.